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Relative importance of environmental variables for the distribution of an invasive marsh species Spartina alterniflora across different spatial scales
The relative importance of environmental variables for Spartina alterniflora distribution was investigated across different spatial scales using Maxent, a species distribution modelling technique. Results showed elevation was the most important predictor for species presence at each scale. Mean diurnal temperature range and isothermality were the second most important at national and regional scales respectively. Soil drainage class, pH and organic carbon were important on the northern Chinese coast. The importance of climatic variable type was the highest at global and national scales and declined as the scale decreased. The importance of soil variable type was less at coarser scales, but varied greatly at finer scales. The relationships between environmental variables and species presence changed as the variables’ ranges changed across different scales. Climatic and soil variables were substantially affected by variables interactions, which changed their relationships to species presence and relative importance. The modeled suitable area on the Chinese coast decreased from 54.16% to 12.64% limited by elevation from global to national scale and decreased to 8.04% limited by soil drainage, pH and organic carbon from national to regional scale. Our findings emphasize the importance of spatial scale for understanding relationships between environmental variables and the presence of S. alterniflora.
MF17100 Accepted 01 November 2017
© CSIRO 2017